Building Envelope
Building Envelope
• Physical separator between interior and exterior spaces– Walls– Floors– Roofs– Fenestrations (any opening in the structure)– Doors
Envelope for Climates
• Respond to the local climate• 4 common extremes– Arid Climate– Tropical Climate – Cold Climate– Mixed Cold/Hot Climate
Arid Climate
• Dry and hot but have large swings of temp. from the day to night
• Thermal mass on the outside is most crucial design strategy to even out temp swings
• Consistently hot locations it helps to have high ceilings and shaded breezeways, light colors, daylighting via reflected light (not direct sun)
• Courtyards with natural ventilation, pools or fountains can provide evaporative cooling
Arid Climate
Tropical Climate
• Hot and humid areas• Keep the heat of the sun off and maximize ventilation,reflective insulated roof with walls that pass breeze but not rain• Light colored
Cold Climate
• Maximize insulation, use windows for solar gain on thermal mass inside the envelope
• Air tight envelope, avoid infiltration
Mixed Cold/Hot Climate
• Flexibility is key to design for this climate• Deep overhangs, allows low winter sun in
through windows to heat up high-mass concrete slab inside, while blocking summer sun
• Light roof/darker walls to repel summer sun but absorb winter sun
• Extra insulation, operable windows
Mixed Cold/Hot Climate
Envelope Energy Flow
• Envelope is a composition of layers with varying thermal and permeability properties
• Composed of membranes, sheets, blocks and preassembled components
• Choice is governed by climate• 2 opposite design concepts– Open frame– Closed shell
Closed shell
• Harsh climates• Closed shell design with carefully placed
openings to make limited contact with the outdoors
• Also useful when there are unwanted external influences (noise, visual clutter)
Open Frame
• When external conditions are close to desired internal conditions
• Open frame with parts of the envelope added to modify outside forces
Envelope Energy Flows
• Flow of heat varies by season and path of heat– Flows from a building in winter and to a building in
summer– Through the building’s skin or outdoor air entering